Ground clamp



Nov. l0, 1931. E. 1 KLlNGl-:L 1,330,947

GROUND CLAMP Filed April 1e, 1927 :Eff/Usual ffingel Patented Nov. 10, 1931 UNITED STATES PATENT GFFICE GROUND CLAMP .Application filed April 18, 1927.

My invention relates to improvements in ground clamps and has for an object thereof to provide a clamp, whereby a good electrical contact between the clamp and the object 5 to which it is applied may be effected regardless of the state of conductivity of the surface of such object.

Another object of the invention resides 1n providing a ground clamp employing an object encircling strap formed to provide teeth adapted to penetrate the surface of the object to which the cla-mp is applied.

Another object of the invention resides in providing means for drawing the strap 5 about an object, whereby the clamping force is exerted in line with the body of the strap.

A further object of the invention resides in providing in a clamp, a strap of sheetmaterial having the margins thereof1 turned on @o the body and formed at intervals with opposed notches to supply paired projections issuing at right angles from and along the edges of the body, which notches are V- shaped and terminate at the verteXes thereof 25 along the edges of the body to provide for the bending of said body on definite transverse lines coincident with opposed notches, and which projections are formed with V-shaped notches at their extremities to supply each thereofl with a pair of spaced teeth for engagement with the surface of a conductor.

A still further object of the invention resides in providing one end of the strap with an eye constructed by slitting the strap for 3@ a short distance transversely at the center of the same, doubling back the end of the strap on a line coinciding with said slit, spreading apart adjacent portions of the strap headed by said slit to form the eye for the reception of a clamp bolt, and forming an aperture in the strap immediately back of said eye to receive the head of such clamp bolt.

An additional object of the invention resides in providing the other end of the strap with transverse rectangular openings for severally receiving the shank of the clamp bolt and the nut thereon, which apertures are spaced apart so that one thereof occurs in each of the several sections of the body of Serial No. 184,679.

the strap defined between the transverse lines on which the body may bend.

lith the foregoing and other objects in view, which will appear in the following description, the invention resides in the novel combination and' arrangement of parts and in the details of construction hereinafter described and claimed.

In the drawings illustrating my invention:

Fig. 1 is a perspective view of an embodiment of my invention applied to a pipe.

Fig. 2 is a perspective view of the strap.

Fig. 3 is an enlarged sectional view taken on line 3-3 of Fig. 2.

Fig. 4 is a developed view of the blank from which the strap shown in Fig. 2, is constructed. v

In employing the clamps now commonly used for grounding to tubes, rods, Water pipes and similar objects, considerable uncertainty T exists as to whether or not suitable contact is made with the grounded structure particularly when corrosion or oxidization of the surface of such structure has taken place. My invention provides a simple and inexpensive clamp adapted to penetrate any fouling surface matter on a grounding object and make good Contact with the metal proper of such object.

The invention proper consists primarily of a strap A of sheet metal adapted to be bent around a pipe or other conductor to which it is to be attached, said strap being constructed to receive a bolt B at the ends thereof for drawing the same securely upon the grounded structure in positive contact therewith.

The strap A includes an elongated body 10 having spa-ced triangular projections 1l, 12 pointing outward in opposed relation from the edges of said body, said strap being constructed from a strip of sheet metal in the longitudinal margins of which V-shaped notches 13, 14 (Fig. 4) are cut to form said triangular projections 11, 12. The vertexes of these notches 13, 14 fall on lines 15, 16 coincident with said edges of the body and with the bases of the projections 11, 12, said projections being bent on said lines into right angular relation with respect to the body (Fig. 2). The tips of the triangular projections 11, 12 are notched as at 17, 18 to form spaced teeth 19, 20. This construction allows the strap to be bent along transverse lines indicated at 21 in Figs. 2 and 4, said lines coinciding with the verteXes of the opposed notches 13 and 14 and allowing the strap to be bent in the form of a polyhedron when applied to a pipe or other cylindrical structure such as indicated at 22 in Fig. 1.

A bolt B is used lfor drawing the ends of the strap A together, an eye C to receive said bolt being provided at one end of 'strap A and formed as follows.: Cutnear one end of the body 10 and between the edges thereofv isa transverse slit v23. ,Said body is doubled back Onitsfelf. along a line 24eXtend ingtransversely across the strap and coinciding with .the slit 23. -The portions of the strap 25 and 26 headed by the slit 23 are lspread apart and formed as shown in Fig. 2and .F ig. 3 to provide the sleeve-like eye C, which extends longitudinally of the body 1() and is adapted to receive the shank oi bolt B. Immediately back of the eye C, the body 10 is-apertured as at 27 to receive the head 28 of the bolt B when the shank 29 thereof is lpassed through said eye C. With bolt B in place in said eye, the head ot said bolt becomes lodged against the shoulder 30 .formed along the edges of the portions 25 and 26 of said eye, whereby a pull uponthe bolt B will be resolved into a direct pull upon vthe body .of the strap. It -is to be noted that the body 10 of the strap A is widened out at the end wherein the eye C is formed (Fig. 4), this being for the purpose of pro'- viding ample strength in that part of the strap adjacent said aperture 27 and for ythe further purpose of providing sufficient metal to form ears 31 capable of and adapted to be bent on the double body portion, whereby the lapping vportions Yof body -A maybe rigidly secured in their eye forming relation.

Along the body 10 of the strap A, Vat 'the end thereof opposite the eye C, are formed .a numberof similar transverse rectangular yopenings 32. These openings are proportioned in length snugly to .receive a nut 33 on bolt B and are slightly wider than the thickness of the nut. Each openingY 32 occupies a position in one of the sections of the body .10 -defined by lines 21, the material Vof each section on the side of the opening 32 nearest eye C bein struck inward, as indicated at 34, in the direction of the projections 11, 12 and the material on the opposite side of the opening being struck outward, as indicated at 35, to provide clearance obliquely through the strap for the shank 29 of bolt B when it fis fitted to the nut caught in the opening.v

For attaching a ground wire to the clamp', -anut l36 is welded or soldered to thestrap 'Aat the side .of the aperture `27 opposite the eye C, the strap having an additional aperture 37 for registration with the bore of the nut 38. Fitting into said nut 36, through said aperture 37, is a screw 38, the saine being supplied with a washer 39 between which washer and the head 28 of screw B a ground wire (not shown) may be clamped.

vIn applying my clamp, the strap A is roughly. bent around the pipe 22 or other conductor to which the clamp is to be affixed, the clamping'bol't B having been first insertedthrough the eye C and the nut 33 started ousaid bolt. The end of the strap formed ,with the openings 32 therein is drawn over the nut '33, said nut being caught in that i .opening 32 nearest thereto.

The bolt B is then .turned into the nut, which is held against ,rotation by the strap and backed against the body 10 along the edge of said opening. Continued turning of the bolt in said nut, causes the shank 29 to be projected through the opening oblique'ly ot' the strap with the result that said strap is ultimately tightly drawn about the conductor. The shank et the bolt after having been passed through opening 32 of the strap `is engageable on opposite sides by the portions 34 of the strap, which hold the bolt and the nut in'plaee. In the first stage of tightening the clamp upon the conductor, the stif'rl sections of the strap, between bending lines 21, having opposed two point bearing through the teeth 19, 20 on projections 11, 12, automaticallv assuine uniform relative angular relation.

And as the tightening progresses. said teeth bite through any foreign fihn or encrustation on thesurtace of the pipe and penetrate into the clear metal ot the pipe, thus effect ing aI permanent and positive electric coin nection between the clamp and the pipe. 7

After the clamp is properly affixed, the protruding end of the strap Vmay be broken off along the line 21 nearest the nut 33, to ieniove the surplus portion ot the said strap which is of no particular use. Thereafter a ground wire is clamped between the washer 39 and the head of, screw 38.

In constructing the strap A, the relative disposition and proportions of the notches 13 and 14 and t-he corresponding lines 2l may be chosen so as to form a standard clamp adaptable to the various sizes of standard conductors on. which the saine is to be applied. Vhenthe clamp is to be used on water pipes or other conductors of similar sizes, the said notches may be formed so that each one of the openings 32 is used for a difierent size of pipe, making the standard bolt B serve in all instances. In this manner the clamp may be readily utilized for all sizes of pipes by simply catching the nut 33 in the proper opening 32 and severing the remaining portion of the band at the proper cross line 21.

My invention is highly meritorious in that lli? it provides a very simple and effective device for making positive and certain electrical contact with a grounded structure. The clamp is adaptable to various sizes of pipe and other conductors, and when attached forms a neat and inconspicuous attachment. The clamp may be struck out of relatively thin sheet metal and employs a standard bolt and nut in conjunction with t-he saine` thereby permitting of marketing the device at a nominal cost. Connections between the strap and the bolt and likewise between said strap and the nut are simple expedients provided in forming the openings 3Q in the strap for the nut 33 and in forming the reinforced eye C by doubling the metal of the strap upon itself. The formation of the eye C in the manner described and the provision of the body spacing projections allowing for the projection of the clamping bolt B, through the strap openings diagonally of the strap, results in directing the clamping force of the bolt 'lengthwise of the body of the strap, whereby relatively great stresses may be met by said stra-p without fracture thereof and whereby contacting pressure between bearing areas of the strap and greun ded conductor is uniformly applied throughout the entire circumference of the conductor. With the body 10 of the clamp spaced apart from the conductor by the relatively spaced projections 11, 12 and by reason of the spaced teeth 19, 20 on said projections, free drainageand evaporation from the Zone of the conductor surface encircled by the strap is permitted, whereby corrosion of parts is minimized with the resultant maintenance of good contact between strap and conductor. The device is sufficiently rigid and of such strength in all its parts that it can withstand great stresses imparted to the same upon the drawing of the ends of the strap together` whereby a sufficient degree of pressure may be had between the teeth of the strap and the surface of the grounding conductor to produce the desired contact.

Changes in the specific form of my invention, as herein disclosed, may be made within the scope of what is claimed without departing from the spirit of my invention.

Having described my invention, what I claim as new and desire to protect by Letters Patent is:

1. In a ground clamp, a strap formed from sheet metal comprising an elongated body having series of opposed triangular projections at its longitudinal edges similarly turned along said edges to point in directions at right angles to the body, said body being adapted to bend, in sections, on transverse lines between adjacent pairs of opposed projections, the tips of said projections being notched to form spaced teeth on each projection for two point contact with a conductor encircled by the strap, said body being formed with a transverse slit medially thereof near one of its ends, the end portion of said body adjacent said slit being bent back upon the body proper on a line coinciding with said slit, the portions of the lapping parts of the body headed by said slit being oppositely bulged to form a sleeve-like eye, marginal portions of said lapping parts being` bent to secure said parts in lapping relation, a bolt, the shank thereof being adapted to be inserted through said eye, said body having an aperture therein to receive the head of the bolt fitted to said eye, a nut for said bolt, said body at its other end having a series of openings therein, one in each body section, said openings being adapted severally to receive the nut and provide for catching it in the body at intervals along the saine, the body in each section at opposite sides of the opening therein being oppositely bulged to clear the shank of the bolt and freely permit of the projection of said shank through the nut and corresponding opening in which the nut is caught, and a screw having a threaded connection with said body for electrically connecting a wire thereto.

2, In a ground clamp, a strap formed from sheet metal comprising an elongated body h ving series of opposed triangular projections at its longitudinal edges similarly turned along said edges to point in directions at right angles to the body, said body being adapted to bend, in sections, on transverse lines between adjacent pairs of opposed projections, the tips of said projections being notched to form spaced teeth on each proj ection for two point contact with a conductor encircled by the strap, said body being formed with a transverse slit medially thereof near one of its ends, the end portion of said body adjacent said slit being bent back upon the body proper on a line coinciding with said slit, the portions of the lapping parts of the body headed by said slit being oppositely bulged to form a sleeve-like eye, a bolt, the shank thereof being adapted to be inserted through said eye, said body having an aperture therein to receive the head of the bolt fitted to said eye, a nut for said bolt, said body at its other end having a series of openings therein, one in each body section, said openings being adapted severally to receive the nut and provide for catching it in the body at intervals along the same, t ie shank of the bolt being adapted to be screwed into said nut and through the opening in the body receiving the nut into strap clamping relation diagonally of the body, and means for electrically connecting a wire to the strap.

3. In a ground clamp, a strap formed from sheet metal comprising an elongated body having series of opposed triangular projections at its longitudinal edges similarly turned along said edges to point in directions at right angles to the body, said body being adapted to bend, in sections, on transverse lines between adjacent pairs of opposed projections, the tips of said projections being notchedto forni spaced teeth on each projection for two point contact With a conductor encircled by said strap, a bolt, said body having an eye at one end thereof to receive said bolt, a nut for the bolt, said body at its other end having a series of openings therein, said openings being adapted severally to receive the nut and provide for catching it in the body at intervals along the saine, the shank of the bolt being adapted to be screwed into said nut and through its receiving opening in the body into strap clamping relation diagonally of the body.

4. In a ground clamp, a strap comprising an elongated body formed with projections .thereon adapted to engage a conductor encircled by said strap, said body being formed with a transverse slit medially thereof near onel of its ends, the end portion of sai-d body adjacent said slit being bent back upon the body proper on a line coinciding with .said slit, the portions of the lapping parts of the body headed by said slit being oppositeiy bulged to form a sleeve-like eye. a b olt, the shank thereof being adapted to be inserted through said eye, said body having an aperture therein to receive the head of the bolt fitted to said eye, a nut for said bolt, said body at its other end having a series of openings therein, said openings being adapted severally to receive the nut and provide for f catching it in the body at intervals along 'the saine, the shank of the bolt being adapted to be screwed into said nut and through the opening in the body receiving the nut into strap clamping relation diagonally of the body.

5. In a ground ciamp, a strap, one end thereof being transversely slitted between'its edges and doubled back upon itselfon a line coinciding with said slit, the body of said strap being apertured adjacentthe doubled back portion thereof, the lapping portions headed by said slit being spread apart to forni an eye for the reception of a clamp bolt, the longitudinal margins of said strap being serrated and bent angularly of the body to provide projections for engagement with the object on which the clamp is to be applied, and means on the other end of the strap for engagement with the nut of said clamp bolt.

6. In a ground clainp,a strap having an elongated body formed with an eye at one end thereof, a headed bolt adapted to pass through said eye and have its head seated against the saine, a nut for said bolt` said strap being adapted to encircle a conductor. the body of the strap having a bolt and nut receiving aperture therein remote from said eye,'said'body at its apeitured portion having laterally spaced projections thereon to engage the conductor and space said portion of the body therefrom.

7. In a ground clamp, a strap formed from sheet metal comprising an elongated body having the edges thereof bent outwardly therefrom at right angles, said edges having notches therein to provide spaced teeth along said edges for engagement with an object on which said clamp is to be applied, means at one end of said body for attaching a bolt thereto, said body at its other end having a series of openings therein adapted to receive the nut of said bolt for drawing the endsof said clanip together, the notches in the edges of said elongated body being of a less depth opposite said openings to strengthen the strap at said openings.

8. A ground clamp Comprising a strap having iianges along the edges thereof, said flanges being formed with notches extending partially into the same to provide spaced teeth, some of said notches eXtendin up to said strap proper to permit of bending the saine at such locations, and means for drawing the ends of the strap together.

In a ground clamp, a strap transversely slit at one end thereof between its edges and doubled back upon itself on a line coinciding vith said slit, the body of said strap being apertured adjacent the doubled back portion, the lapping portions headed by said slit being pressed apart to form an eye for the reception of the shank of a clamp bolt, the head thereof being inserted within said aperture, and means on the other end of said s rap for engagement with the nut of said clamp bolt. l0. In a ground clamp, a strap having an elongated body formed with an eye at one end thereof, the axis of said eye extending longitudinally of the strap in the plane thereof, a headed bolt adapted to pass through said eye, said body having an aperture adjacent said eye to receive the head of .said bolt, and means at the other end of said strap for engagement with said bolt for drawing the ends of said strap together. Y

il. In 'a ground clamp, al strap formed from sheet metal adapted to be bent along certain transverse lines, projections formed on said strap intermediate said lilies. a bolt attached at one end to one end of said strap, and a series of openings in said strap at the other end for engagement with said bolt to draw the ends of said strap together, said openings being spaced the same distance apart as said lilies along which said strap is lient.

12. In a ground clamp, a strap having a body formed with an eye at one end thereof for the reception of a headed bolt, a seat on said eye for the head of said bolt, said body at said seat lying in a plane containing the axis of said eye.

13. In aground clamp, a strap, one end thereof being transversely slitted at its center and doubled back upon itself in line with said slit, the portions of the strap headed by said slit being spread apart to form an elongated eye for the reception of the shank of a clamp bolt, means at one end of the eye for the reception of the head of the clamp bolt, and means at the other end of the strap for engagement with a nut for said clamp bolt.

14. In a ground clamp, a strap having an opening therein, an eye at one end of said strap, a clamp bolt extending through said eye and passing through the opening of said strap in oblique relation to said strap, and a nut on said bolt received Within said opening and seated against an edge of said strap formed by said opening, the portions of said strap adjacent said opening being engageable with said bolt on opposite sides thereof and on opposite sides of said nut to hold said nut Within said opening.

In testimony whereof I have affixed my signature to this specication.

-EDWARD L. KLINGEL. 

